Best Endings in Science Fiction/Fantasy

John Ottinger III of Grasping for the Wind has asked several authors for their favorite SF endings. By no coincidence, John De Nardo over at SfSignal asked about both the best and the worst endings.

Well, clearly there is a trend. Since my name is John, I also must answer the question.
My favorite endings in books come from a list a little different from what the worthies named above listed. This could be due to age, or taste, or some other factor. Maybe I have a penchant for surprise endings...